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Publication numberUS4379657 A
Publication typeGrant
Application numberUS 06/161,235
Publication dateApr 12, 1983
Filing dateJun 19, 1980
Priority dateJun 19, 1980
Publication number06161235, 161235, US 4379657 A, US 4379657A, US-A-4379657, US4379657 A, US4379657A
InventorsKarl J. Widiner, Riley G. Goldsmith
Original AssigneeConoco Inc.
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Riser tensioner
US 4379657 A
Abstract
A modular riser tensioner has a frame (10) for mounting on a platform deck with air (16,18) and oil (20,22) accumulators mounted on a mounting frame and connected to cylinders (24-30) also on the mounting frame. A piston (32) located within the cylinders carries a riser tensioning ring (50) for supporting the riser. Pairs of cylinders are located on opposite sides of the riser and connected to an oil accumulator independent of the other cylinders.
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Claims(2)
We claim:
1. A portable modular riser tensioner for supporting risers from a floating platform comprising: a mounting frame having peripheral supports for supporting said frame from the platform and a central opening; a riser tensioning ring having a central opening and means for supporting a riser within said central opening of said riser tensioning ring; at least two pairs of cylinders, one of each of said pair of cylinders being diametrically opposed to the other of said pair; a piston having a rod end slideable in each of said cylinders; at least two oil accumulators; at least two air accumulators; said cylinders, said oil accumulators and said air accumulators all connected to one of said mounting frame and said tensioning ring; said piston connected to the other of said mounting frame and said tensioning ring through said rod ends; an upper portion of each of said air accumulators in fluid communication with an upper portion of a corresponding oil accumulator; and a lower end of an oil accumulator in fluid communication with a corresponding pair of said diametrically opposed cylinders at the rod end of said piston.
2. A modular riser tensioner as in claim 1 wherein said cylinders are connected to said mounting frame.
Description
BACKGROUND OF THE INVENTION

The invention relates to offshore oil production and in particular to a modular apparatus for tensioning production risers to a floating platform.

In the production of oil to a tensioned leg floating platform a conductor or riser has its lower end secured to a connection at the seabed. The upper end of the riser is terminated at the platform. The marine riser will collapse if not partially or completely supported at the upper end. It, therefore, is conventionally supported by a tensioned forced applied at the upper end of the riser.

Because of the relative motion between the platform and the seabed caused by wave and tide actions, some device is required to maintain the tension while permitting the relative motion.

This has conventionally been accomplished on other types of floating vessels with hydraulic-pneumatic tensioning devices mounted on the vessel structure and connected to the riser with a plurality of wire ropes. The conventional method requires considerable deck space and makes changing of tensioners between various locations difficult and impracticable for floating platform use. The wire rope requires constant maintenance, is subject to wear with potential failure, and the use of the rope delays the response time of the tensioning system.

SUMMARY OF THE INVENTION

A modular riser tensioner for supporting a riser from a floating platform includes a mounting frame which has means for supporting the frame from the platform, and which has a central opening. A riser tensioning ring, also having a central opening, includes a means for supporting a riser therewithin. At least four vertical cylinders and corresponding pistons are located equally spaced around the central opening. Pairs of opposing cylinders are manifolded to corresponding oil accumulators which are in turn manifolded to corresponding air accumulators. The cylinder and the accumulators are connected and supported on either the mounting frame or the riser tensioning ring. The piston is connected to the other of the supporting frame or riser tensioning ring.

Accordingly, the invention comprises a portable, compact modular structure carrying the accumulator cylinders as a part of the frame. The apparatus has a faster response time than the type using wire rope and does not have the problems of rope wear and breakage. It is a relatively small modular unit which may be readily moved for use at various locations and easily interchanged. The elements contribute to a long operational life with a minimum of maintenance.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a side elevation of the tensioner, and

FIG. 2 is a plan view of the riser.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A tensioned leg platform has in its deck a square recessed opening, not shown. The modular tensioner has a generally square mounting frame 10 which is peripherally supported by the deck and which has a central opening 12 in which the riser to be supported is located. The frame also includes centralizing rollers 14 which are spring loaded and operate simply to maintain the riser centrally within the opening.

Two air accumulators 16 and 18 are mounted on the bottom of the mounting frames as are two oil accumulators 20 and 22. Also directly connected to the mounting frame are four cylinders 24, 26, 28, and 30.

Located within each of the cylinders is a corresponding piston 32 with a piston rod 38 attached thereto and with the rod end of the cylinder being sealed against the rod.

An interconnecting pipe 40 connects the upper end of oil accumulator 20 and air accumulator 16. A corresponding line interconnects accumulators 18 and 22. A second interconnecting pipe 42 connects the bottom of oil accumulator 20 with cylinders 24 and 28 with the connection to the cylinders being on the rod side of the piston.

A charging connection 44 is located in each of the air accumulators to permit intermittent charging of the system from an external air pressure source, not shown. The amount of load to be carried is varied by charging the air accumulator up to a necessary pressure with the system acting as a pneumatic spring thereafter. The air pressure acting through the oil accumulator forces oil into the rod side of piston 32 thereby supporting a load which is a function of the pressure existing within the system.

The accumulators 18 and 22 are connected in a corresponding manner to cylinders 26 and 30. It can be seen that a single accumulator is connected to cylinders located on opposite sides of the riser and, accordingly, both cylinders must operate at identical pressures. This prevents uneven loading on the two sides exerting a bending moment on the riser. Furthermore, should either of the systems be out of operation, the remaining system can carry the load by increasing the pressure within the active air accumulator system.

The rods 38 of the piston are extended downwardly and are directly connected to a riser tensioning ring 50. This ring includes a central opening 52 and locking dogs 54 which engage and support a riser system passing through the central opening.

The riser tensioner is modular and fits readily within a compatible opening within the deck. The frame 10 carries with it the accumulators 16, 18, 20, and 22 as well as the support cylinders. The modular unit includes the pistons and piston rods 38 which support the riser tensioning ring thereby providing a compact modular unit requiring no wire rope or support. The only connection to on-deck equipment is intermittent connection required for charging of the air accumulators when required.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2841961 *Apr 13, 1953Jul 8, 1958Delong CorpOff-shore drilling barge
US3171259 *Sep 30, 1960Mar 2, 1965Universal Drilling Company IncOffshore drilling barge
US3378086 *May 13, 1966Apr 16, 1968Geocon LtdStationary overwater platform
US3718316 *Sep 4, 1970Feb 27, 1973Vetco Offshore Ind IncHydraulic-pneumatic weight control and compensating apparatus
US3955621 *Feb 14, 1975May 11, 1976Houston Engineers, Inc.Riser assembly
US4004532 *May 5, 1975Jan 25, 1977Western Gear CorporationRiser tension system for floating platform
US4121806 *Mar 18, 1977Oct 24, 1978Societe Nationale Elf Aquitaine (Production)Apparatus for compensating variations of distance
US4142584 *Jul 20, 1977Mar 6, 1979Compagnie Francaise Des PetrolesTermination means for a plurality of riser pipes at a floating platform
US4213720 *Sep 5, 1978Jul 22, 1980Vickers LimitedTensioning of members
Non-Patent Citations
Reference
1 *ETA Chapter from "The Technology of Offshore Drilling", Completion and Production, Compiled by ETA Offshore Seminars, Inc.
2 *Vetco Offshore, Inc., Catalog, pp. 5890, 5891.
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4576517 *Oct 19, 1984Mar 18, 1986501 Vickers PLCMarine heave compensating device
US4596494 *Dec 17, 1982Jun 24, 1986Ateliers Et Chantiers De Bretagne-AcbDevice for positioning and applying tension to a set of rods for holding a partially submerged platform
US4662786 *Oct 3, 1985May 5, 1987Cherbonnier T DaveDynamic load compensating system
US4712620 *Jan 31, 1985Dec 15, 1987Vetco Gray Inc.Upper marine riser package
US4729694 *Jun 30, 1986Mar 8, 1988Lockheed CorporationTLP marine riser tensioner
US4733991 *Dec 1, 1986Mar 29, 1988Conoco Inc.Adjustable riser top joint and method of use
US4759662 *Oct 9, 1987Jul 26, 1988Lockheed CorporationTLP marine riser tensioner
US4799827 *Nov 17, 1986Jan 24, 1989Vetco Gray Inc.Modular riser tensioner incorporating integral hydraulic cylinder accumulator units
US4808035 *May 13, 1987Feb 28, 1989Exxon Production Research CompanyPneumatic riser tensioner
US4881852 *Jan 22, 1988Nov 21, 1989Exxon Production Research CompanyMethod and apparatus for tensioning the tethers of a tension leg platform
US4883387 *Jun 29, 1988Nov 28, 1989Conoco, Inc.Apparatus for tensioning a riser
US4883388 *Apr 8, 1987Nov 28, 1989Cherbonnier T DaveLoad compensating system
US4886397 *Aug 27, 1987Dec 12, 1989Cherbonnier T DaveDynamic load compensating system
US4913592 *Feb 24, 1989Apr 3, 1990Odeco, Inc.Floating structure using mechanical braking
US4934870 *Mar 27, 1989Jun 19, 1990Odeco, Inc.Production platform using a damper-tensioner
US5163513 *Jun 28, 1991Nov 17, 1992Bowen Tools, Inc.Circle threadform for marine riser top joint
US5366324 *Jun 18, 1992Nov 22, 1994Ltv Energy Products Co.Riser tensioner system for use on offshore platforms using elastomeric pads or helical metal compression springs
US5482406 *Apr 15, 1993Jan 9, 1996Continental Emsco CompanyVariable spring rate compression element and riser tensioner system using the same
US5628586 *Jun 23, 1995May 13, 1997Continental Emsco CompanyElastomeric riser tensioner system
US5641248 *Apr 4, 1995Jun 24, 1997Continental Emsco CompanyVariable spring rate compression element and riser tensioner system using the same
US5658095 *Oct 12, 1994Aug 19, 1997Continental Emsco CompanyRiser tensioner system for use on offshore platforms using elastomeric pads or helical metal compression springs
US5775845 *Jan 17, 1997Jul 7, 1998Sea Engineering Associates, Inc.Passive riser tensioner
US5846028 *Aug 1, 1997Dec 8, 1998Hydralift, Inc.Controlled pressure multi-cylinder riser tensioner and method
US5873678 *Dec 23, 1996Feb 23, 1999Continental Emsco CompanyTension adjustment mechanism employing stepped or serrated ramps for adjusting tension of a tendon from a floating marine platform
US6431284 *Oct 3, 2000Aug 13, 2002Cso Aker Maritime, Inc.Gimbaled table riser support system
US6530430 *Jun 14, 2001Mar 11, 2003Control Flow Inc.Tensioner/slip-joint assembly
US6554072 *Nov 30, 2001Apr 29, 2003Control Flow Inc.Co-linear tensioner and methods for assembling production and drilling risers using same
US6585455Nov 19, 1996Jul 1, 2003Shell Oil CompanyRocker arm marine tensioning system
US6692193 *Oct 2, 2001Feb 17, 2004Technip FranceDedicated riser tensioner apparatus, method and system
US6739395 *Jan 15, 2003May 25, 2004Control Flow Inc.Tensioner/slip-joint assembly
US6968900Dec 9, 2002Nov 29, 2005Control Flow Inc.Portable drill string compensator
US7008340Dec 9, 2002Mar 7, 2006Control Flow Inc.Ram-type tensioner assembly having integral hydraulic fluid accumulator
US7112011Dec 3, 2004Sep 26, 2006Vetco Gray Inc.Hydro-pneumatic tensioner with stiffness altering secondary accumulator
US7219739Mar 7, 2005May 22, 2007Halliburton Energy Services, Inc.Heave compensation system for hydraulic workover
US7314087Mar 7, 2005Jan 1, 2008Halliburton Energy Services, Inc.Heave compensation system for hydraulic workover
US7588393 *Sep 2, 2008Sep 15, 2009Atp Oil & Gas CorporationMethod for supporting top tension drilling and production risers on a floating vessel
US7686085 *Apr 3, 2007Mar 30, 2010Vetco Gray Inc.System, method, and apparatus for sleeved tensioner rod with annular adhesive retention
US7819195Apr 16, 2007Oct 26, 2010Vetco Gray Inc.External high pressure fluid reservoir for riser tensioner cylinder assembly
US7823646Nov 16, 2005Nov 2, 2010Vetco Gray Inc.Riser tensioner with lubricant reservoir
US7886828 *Sep 2, 2008Feb 15, 2011Atp Oil & Gas CorporationFloating vessel for supporting top tension drilling and production risers
US8083440Aug 7, 2009Dec 27, 2011Diamond Offshore Drilling, Inc.Riser tensioner restraint device
US8141644 *Sep 14, 2005Mar 27, 2012Vetco Gray Inc.System, method, and apparatus for a corrosion-resistant sleeve for riser tensioner cylinder rod
US8245786 *Mar 30, 2010Aug 21, 2012Vetco Gray Inc.System, method and apparatus for sleeved tensioner rod with annular adhesive retention
US8496409Mar 25, 2011Jul 30, 2013Vetco Gray Inc.Marine riser tensioner
US8579034 *Apr 4, 2012Nov 12, 2013The Technologies Alliance, Inc.Riser tensioner system
US8746351 *Jun 23, 2011Jun 10, 2014Wright's Well Control Services, LlcMethod for stabilizing oilfield equipment
US20120247783 *Apr 4, 2012Oct 4, 2012The Technologies Alliance, Inc. (dba OilPatch Technologies)Riser tensioner system
US20120325487 *Jun 23, 2011Dec 27, 2012David WrightSystems and methods for stabilizing oilfield equipment
US20130230358 *Mar 5, 2013Sep 5, 2013Cameron International CorporationOffshore System with Subsea Riser
EP0270335A2 *Nov 30, 1987Jun 8, 1988Conoco Inc.Method and apparatus for tensioning a riser
EP0349267A1 *Jun 27, 1989Jan 3, 1990Conoco Inc.Apparatus for tensioning a riser
EP0385932A2 *Feb 14, 1990Sep 5, 1990Odeco Inc.Mechanical damper system for a floating structure
EP0390728A2 *Feb 14, 1990Oct 3, 1990Odeco Inc.System for damping the heave of a floating structure
EP0894939A2Aug 3, 1998Feb 3, 1999Hydralift ASAControlled pressure multi-cylinder riser tensioner and method
EP1359287A2 *May 2, 2003Nov 5, 2003Moss Maritime ASRiser Guide
Classifications
U.S. Classification405/224.4, 405/303, 405/168.4
International ClassificationE21B19/00, E21B7/128
Cooperative ClassificationE21B7/128, E21B19/006
European ClassificationE21B19/00A2B, E21B7/128
Legal Events
DateCodeEventDescription
Mar 16, 1987ASAssignment
Owner name: VETCO GRAY INC.,
Free format text: MERGER;ASSIGNORS:GRAY TOOL COMPANY, A TX. CORP. (INTO);VETCO OFFSHORE INDUSTRIES, INC., A CORP. (CHANGED TO);REEL/FRAME:004748/0332
Effective date: 19861217
Feb 5, 1987ASAssignment
Owner name: CITIBANK, N.A.,
Free format text: SECURITY INTEREST;ASSIGNOR:VETCO GRAY INC., A DE. CORP.;REEL/FRAME:004739/0780
Effective date: 19861124
May 1, 1986ASAssignment
Owner name: VETCO OFFSHORE INDUSTRIES, INC., 7135 ARDMORE ROAD
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:VETCO OFFSHORE, INC.;REEL/FRAME:004539/0568
Effective date: 19860416